Doc: make python function/method descriptions look as in Python

[Eli Zaretskii]

> From: Phil Muldoon <pmuldoon@redhat.com>
> Cc: <gdb-patches@sourceware.org>
> Date: Tue, 06 Sep 2011 20:36:14 +0100
> 
> <Paul_Koning@Dell.com> writes:
> 
> > Here is an updated version.  This one replaces defmethod by defun and defivar by defvar, with the class name explicit on the symbol as is the Python documentation convention.  I'm sending the diff as an attachment, hope that works right.
> 
> I think it is great.  If Eli is fine with it, and it meets the standards
> of the GDB manual, I think it would be an improvement.

I'm fine with it, if Paul decided not to do anything about collapsing
@r{]}@r{]} and the slanted parentheses look okay in print.